The rubber stopper sterilization process can lead to adhesion of one stopper to one or more other stoppers, forming a clump. If only two stoppers associate, the interaction is referred to as a "twin". Typically, the twinning phenomenon occurs along the largest flat surface of the components. Stopper twins created as a result of sterilization processes are formed by the treatment of the components with high heats and compression.
Sterile pharmaceuticals are often filled under sterile or aseptic conditions, in an environmentally-controlled aspetic room. Recently, self-contained aseptic filling lines have been developed for filling sterile pharmaceuticals. Self-contained aseptic filling lines, also known as barrier filling lines, eliminate the need for sterile rooms. Barrier filling lines, in which rubber stoppers are used to seal glass or plastic vials, are particularly susceptible to downtime as a result of stopper twins. During the sealing process, stoppers are fed from a sorting bowl onto a rotary wheel which places the stoppers on the vials. When a significantly high number of stopper twins are present in the sorting bowl, single stoppers are unable to be fed onto the rotary wheel for placement on the vials. When this occurs, the filling line must be halted, at which time an operator manually removes the stopper twins from the sorting bowl and replaces them with single, separated stoppers. The filling line is then restarted and filling resumed. Stopper twins are either separated or discarded. Currently, the most effective method for the separation of stopper twins is to separate the twins manually. However, this method does not eliminate the stopper twins and need for frequent shutdowns in order to clear the hopper of twins. Moreover, if the stopper is being used under aseptic conditions, human intervention can lead to greater risk of product contamination. Forceful manual separation methods can increase the amount of particulate matter released during the separation process, which may result in a defective product. Taken together, these problems lead to greater down time, the risk of compromised sterility and increased component waste.
The problem of stopper twinning presents itself in its most pronounced form when stoppers are sterilized under high heats and compression and occurs to varying extents regardless of the type of rubber used in the manufacture of the stoppers or the type of post-manufacture treatments. Stoppers subjected to silicone baths to prevent twinning and provide for a better seal and other pre-sterilization procedures are still prone to twinning. Stopper twinning is therefore seen as a problem that exists wherever sterile stoppers are required. As such, there exists a need for a device that will separate stopper twins without requiring shutdown of an entire filling line.
Devices to address the problem of stopper twinning are not known in the art. Early devices designed by the inventors of the instant invention have all suffered from the inability of the rollers to "grab" the twins and draw them into the rollers for separation. This problem is solved by the unique roller geometry disclosed in the instant invention.
Currently, there is no efficient method for the separation of stopper twins, nor has any solution to the problem been implemented by workers in the fields of either manufacturing or engineering. The only existent devices similar to the instant invention are inapplicable to the problem of stopper twinning and can be used in article sorting and singling only.
The primary object of the instant invention is the separation of stopper twins. Secondary objectives of the invention include the potential for placement of the device on a filling and/or packaging line or its use as a stand-alone component, at the discretion of the operator, and the option to include the invention in-line with high speed and/or sterile filling lines.